--- old/src/java.base/share/classes/jdk/internal/misc/Unsafe.java	2018-12-07 12:57:57.000000000 -0800
+++ new/src/java.base/share/classes/jdk/internal/misc/Unsafe.java	2018-12-07 12:57:56.000000000 -0800
@@ -181,6 +181,15 @@
         return c.isValue() && c == c.asValueType();
     }
 
+    private static final int JVM_ACC_FLATTENED = 0x00008000; // HotSpot-specific bit
+
+    /**
+     * Returns true if the given field is flattened.
+     */
+    public boolean isFlattened(Field f) {
+        return (f.getModifiers() & JVM_ACC_FLATTENED) == JVM_ACC_FLATTENED;
+    }
+
     /**
      * Returns true if the given class is a flattened array.
      */
@@ -250,6 +259,88 @@
      */
     public native <V> void putValue(Object o, long offset, Class<?> vc, V v);
 
+    /**
+     * Starts a private buffer
+     */
+    public native <V> V startPrivateBuffer(V value);
+
+    public native <V> V finishPrivateBuffer(V value);
+
+    /**
+     * Updates an int field of a value instance of type {@code V}
+     * addressed by the given {@code o} object at the given offset
+     * with {@code x} and returns the new value.
+     *
+     * Unless the reference {@code o} being stored is either null
+     * or matches the field type, the results are undefined.
+     *
+     * @param vc Value class V
+     * @param o Java heap object in which the variable resides, if any, else
+     *        null
+     * @param offset indication of where the variable resides in a Java heap
+     *        object, if any, else a memory address locating the variable
+     *        statically
+     * @param x the value to store into the indicated Java variable
+     * @param <V> Value class
+     * @return an instance of the given value class
+     */
+    public native <V> V withInt(Class<V> vc, Object o, long offset, int x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withBoolean(Class<V> vc, Object o, long offset, boolean x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withByte(Class<V> vc, Object o, long offset, byte x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withShort(Class<V> vc, Object o, long offset, short x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withChar(Class<V> vc, Object o, long offset, char x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withLong(Class<V> vc, Object o, long offset, long x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withFloat(Class<V> vc, Object o, long offset, float x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withDouble(Class<V> vc, Object o, long offset, double x);
+
+    /** @see #withInt(Class, Object, long, int)  */
+    public native <V> V withReference(Class<V> vc, Object o, long offset, Object x);
+
+    /**
+     * Updates a field of a value instance of type {@code V} addressed by
+     * the given {@code o} object at the given offset with {@code x}
+     * and returns the new value.
+     *
+     * Unless the reference {@code o} being stored is either null
+     * or matches the field type, the results are undefined.
+     *
+     * @param vc Value class V
+     * @param o Java heap object in which the variable resides, if any, else null
+     * @param vc_offset indication of where the variable resides in a Java heap
+     *        object, if any, else a memory address locating the variable
+     *        statically
+     * @param xc_offset offset from the field addressed by o and vc_offset
+     * @param xc The type of the field to be updated
+     * @param x the value to store into the indicated Java variable
+     * @param <V> the containing class
+     * @param <X> the field type
+     * @return an instance of the given containing class
+     */
+    public native <V,X> V withValue(Class<V> vc, Object o, long vc_offset, long xc_offset, Class<X> xc, X x);
+
+    /**
+     * Returns the header size of the given value class
+     *
+     * @param vc Value class
+     * @param <V> value clas
+     * @return the header size of the value class
+     */
+    public native <V> long valueHeaderSize(Class<V> vc);
+
     /** @see #getInt(Object, long) */
     @HotSpotIntrinsicCandidate
     public native boolean getBoolean(Object o, long offset);